On a hot afternoon in early August, almost 200 bumblebees lie dead on a dusty forest track bordering a solar-panel-clad patch of arable land in northern Germany. Entomologists highlight that dead bumblebees naturally concentrate when workers reach the end of their four-to-six-week lifespan and are discarded from the nest. Yet, recent research suggests that summer heatwaves may be scorching our bees, with intense heat and drought disrupting their biological and behavioural processes.

Compounded by pesticide use, pathogens, and habitat loss, global warming continues to threaten pollinators – responsible for one of our most vital services [1]. With increasing areas barren of the flowers needed for essential nectar and pollen, pollinators are in dire need of a lifeline.

Three out of four food crops we eat rely on insect visitors – a service worth around €15bn a year across Europe [2]. Without pollinators, some crops fail to form fruit or seeds entirely, while others produce stunted, misshapen harvests [3].

Out of roughly 25,000 known bee species on Earth, only about 270 are bumblebees – yet they punch well above their weight in supporting our food systems. Tomatoes, for example, lock their pollen away tightly. Only the strong vibration of a bumblebee (the sound we hear as a distinct buzz) can shake it loose [3]. If pollinator numbers continue to drop, growers face a tedious reality: hand-pollinating crops by flicking individual blossoms or buzzing each flower with an electric toothbrush to dislodge the pollen.

Thick coats and round bodies make bumblebees well-adapted to survival in cool climates. But these features mean that they are susceptible to overheating when temperatures run high [4]. Keeping cool is exhausting; if a bee cannot maintain its optimal body temperature, it is less able to ward off infections [5]. Bumblebees also thermoregulate to maintain brood temperature for the proper development of their young. Research at the University of Sussex found that during heatwaves, British buff-tailed bumblebee workers were unable to maintain optimal brood temperatures [6].

Outside the nest, extreme heat can prevent bees from locating food. Experiments in Germany show that during heatwaves, bumblebees’ responses to floral scents (used by plants to attract pollinators) decrease [1].

Figure 1: A Cuckoo bee rests on a flower. Courtesy of Teilo Rogers (April 2026), Caerphilly, UK.